1. Fields of the Invention
The present invention relates to an adjustment device, and more particularly, to an adjustment device using magnetic members and movable members to adjust the resistance of an exerciser.
2. Descriptions of Related Art
The conventional exercisers comprise a driving device and a magnetic resistance device, the magnetic resistance device has a flywheel and a magnetic member. The user operates the driving device to output a force to drive the flywheel. The magnetic operation between the magnetic operation face of the flywheel and the magnetic member generates a resistance to the driving device, and the user overcomes the resistance to exercise the muscles. U.S. Pat. Nos. 5,145,480, 5,310,392, 5,324,242 and 6,569,063 disclose a similar magnetic resistance device which has a magnetic member and a movable device. The movable device moves the magnetic member to close the flywheel to cause magnetic field cutting to generate the resistance. There is a movable block with a U-shaped cross section and two magnetic members are connected on two extensions of the U-shaped movable block. The two magnetic members face the two opposite sides of the flywheel. However, in order to prevent the recessed portion of the U-shaped movable block from contacting the flywheel, the distance that the magnetic members can move relative to the flywheel has to be narrowed or reduced. Alternatively, the size of U-shaped movable block has to be increased, and this affects the manufacturing cost. Besides, the movable device is not well arranged so that the movement of the magnetic members is not smooth as desired.
The present invention intends to provide an adjustment device to eliminate the shortcomings mentioned above.